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innovative
10-12-2008, 01:05 PM
i am new to this site and decided to give a try for one of my units i am having trouble with what i have is an overcharge i think but i want to check subcooling to verify charge in unit problem is the unit has a fan cycle switch the ambient temp out side is 20 f. can i bypass the fan cycle to allow for a constant air flow allowing me to check the a accurate subcooling reading or is there a better way of checking for an overcharge in a freezer in a low ambient temp.

joe magee
11-12-2008, 06:23 AM
Why do you think it's overcharged? does it have a receiver and sight glass?

Sledge
11-12-2008, 06:38 AM
If it is outside, and you bypass the fan control to give constant air flow, you will over cool the condensor, which will give it the appearance of being undercharged.

You are running this unit in winter conditions...do you have a headmaster on it? I am thinking that when it gets really cold, even with a fan control you will over condense this unit, unless you also have a head master. But if you have a head master, you dont need to cycle the fan.

More info is needed.

innovative
11-12-2008, 12:53 PM
thanks for the reply's i have got it all figured out i knew it was over charged because i had one of my new guys watching the scale while i finished up with the contractor when i came back out in stead of shutting the gauges off at 8 lbs of gas he just let it suck the refrigerant in and when i looked at the scale it said 17lbs double the charge of what was need i knew i had to pull the gas out but i didnt know with the winter temps out side if i could still get a subcooling value when bypassing the fan it would make some sense but i would also had to bolck the air flow across the condenser to get a higher condensing temp right or should i justs go off of superheat in the winter.

Brian_UK
12-12-2008, 12:15 AM
thanks for the reply's i have got it all figured out i knew it was over charged because i had one of my new guys watching the scale while i finished up with the contractor when i came back out in stead of shutting the gauges off at 8 lbs of gas he just let it suck the refrigerant in and when i looked at the scale it said 17lbs double the charge of what was need i knew i had to pull the gas out but i didnt know with the winter temps out side if i could still get a subcooling value when bypassing the fan it would make some sense but i would also had to bolck the air flow across the condenser to get a higher condensing temp right or should i justs go off of superheat in the winter.
....and breathe :D

The odd full stop would make reading this soooo much easier ;)

Goober
12-12-2008, 02:01 AM
Seriously....this site has got some good stuff, but this just sounds like a wind up. If you know that the system takes 8lbs and your offsider put in 17lbs...well let me think....mmmmmmmmmmm....maybe take out 9lbs.....and I'm breathing, slowly in, slowly out....

innovative
16-12-2008, 02:50 AM
Seriously....this site has got some good stuff, but this just sounds like a wind up. If you know that the system takes 8lbs and your offsider put in 17lbs...well let me think....mmmmmmmmmmm....maybe take out 9lbs.....and I'm breathing, slowly in, slowly out....
so some how you read the post and opened your mouth and sh*t fell out and still couldn't answer the question at had mabe next you can tell me how to hook up my gauges please???????

Gary
16-12-2008, 11:54 PM
i didnt know with the winter temps out side if i could still get a subcooling value when bypassing the fan it would make some sense but i would also had to bolck the air flow across the condenser to get a higher condensing temp right or should i justs go off of superheat in the winter.

I'm assuming this is a TXV system?

Without bypassing or blocking, add refrigerant until the superheat is right. At this point there is sufficient refrigerant for current conditions. This is the minimum charge (although this may not be enough for colder conditions).

Next, block off the condenser until the head pressure simulates summer temperatures.

Now add refrigerant until the subcooling is about 15F/8.5C. This is the maximum charge (although this could be too much for warm weather operation if the receiver is undersized).

Anywhere in between will do the job.

Goober
17-12-2008, 01:35 AM
Somebodies got a short fuse........I do most humbly apologize for offending thee........:confused:

Gary, you have the patience of a saint and I like your posts.